Following on from Coulomb's "BLUE IS POSITIVE": What's wrong with this picture? (2 things)

EVWorks assures me that this is how they all arrive from the manufacturer and that we must ignore the polarity markings so solidly embossed in the motor end casting.

The other problem is a bit hard to spot without more information. Here's the clue: The four yellow zinc bolts seen side-on (3/8" UNF) are all the same length and are all screwed in as far as they will go. The two clear zinc bolts seen head-on (M8) were screwed in first.

That's right. The near lower 3/8" bolt has run into the M8 bolt inside the manifold block, which incidentally is aluminium alloy rather than stainless steel as I first thought.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

Blue and Brown wires appear to be the colours of choice for the Chinese. When I received my 12 chargers they all had Blue and Brown wires on the outputs. On a nicely made sticker on the charger(s)it said that Blue was positive. When I measured a charger I found that Brown was positive - on ALL of them.

I think the Chinese are determined to meet the US market, where, for AC, black is live, and white is ground. So the red/black scheme for low DC voltage would cause problems, since US customers might tend to assume a black wire was positive. So perhaps they use the (international standard) brown/blue for pos/neg. That's what I do when I lack red wire - though I also use red heatshrink in patches. In the same way, they follow the US market by supplying those dreadful imperial bolt and thread forms. Fortunately, it seems the Japanese stuck to metric for their exports.
By the way, as someone brought up in primary school on problems like " Find the cost of 1000 acre-feet of water at 4 1/2 d a gallon" (no calculators back then) the metric system couldn't come soon enough.
Finally, a note of appreciation for all these posts from SI units. I love the still life with pump and pear.
And am always interested in studying people's bookshelves.

So the red/black scheme for low DC voltage would cause problems, since US customers might tend to assume a black wire was positive. So perhaps they use the (international standard) brown/blue for pos/neg.

Much as I'd like to blame the Americans for this too, I can't see it. We're talking automotive wiring here. In that context, Americans are used to black being zero volts (chassis potential). US car makers GM and Ford use it, same as most other car makers around the world. In their single-phase ac house wiring both black and red are "hot" (red is switched).

And as you say, the whole world, including America and China, has had to get used to appliance cords where blue is neutral and brown is hot/live/active.

So when presented with an automotive device having blue and brown, instead of the expected black and red, you can either map the colours by their distance in some perceptually-based 3D color space (where red and blue are about as far apart as you can get), or map their functions as neutral = chassis, active = hot. Either way you end up with the same result, given that all cars are now negative chassis.
neutral
blue < > chassis - zero volts
black

active
brown < > hot - positive voltage
red

But what we've found now with both our vacuum pump and the Hall effect throttle box from EVWorks, and what Johny has found marked on his chargers, is exactly the opposite to the above. I've asked EVWorks and they don't know why their Hall effect throttle boxes come wired like that either.

Despite all this, there are apparently a few car makers that use brown instead of black for zero volts, and yes, brown and black are perceptually similar. But I only found one that also uses blue for hot, actually blue with a yellow stripe, at least for the constant +12 V wire to their car radios. Toyota! Seehttp://ccs.exl.info/carwires.html

Now I've spent waaay too much time researching this and I'll soon be getting a phone call from Newton asking why I'm not cutting, welding, grinding or painting.

But here's another amusing tidbit about our power steering pump. Both EVWorks and I have confirmed that the end mounting bolts are metric while the side ones are UNF, a fine american thread (no pun intended, but possibly some irony). Now I've just learned from EVWorks what the hydraulic port threads are. These three sets of threads are all in the same block of aluminium so presumably by the same manufacturer. Can you guess what type of thread the ports are?

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

Now I've just learned from EVWorks what the hydraulic port threads are. These three sets of threads are all in the same block of aluminium so presumably by the same manufacturer. Can you guess what type of thread the ports are?

BSPP or BSPT? These are the most common thread types when it comes to hydraulics from what I remember. the easy way to remember diameter sizes is they are multiples of 1/16" It sounds complicated but once you get the hang of th system it really is easy to work with.

T1 Terry

Last edited by T1 Terry on Tue, 04 Oct 2011, 10:51, edited 1 time in total.

Actually, looking closer I'd say the brass fitting for the oil return is BSPT and the others are BSPP. I would be very surprised if it's any of the metric threads, they are usually proprietary to the heavy equipment manufacturing mobs. I think CAT even have one of their own.

You guessed it! It has already got metric and US threads and contradictory polarity markings, so the other thread just had to be BSP. Specifically 1/4" BSP.

The fact that the female thread is rarely tapered, lends support to your argument James, but I'm afraid it is parallel, not tapered.

British Standard Pipe. A system where, like the incompatible USA system, the fractional inch designation is not an actual measurement, even approximately, of any aspect of the thread). 1/4" BSP is 0.518" 19 TPI 55° (13.157 mm x 1.337 mm).

At least that's what EVWorks think it is. Trouble is, when I measure the only thing I can measure with sufficient accuracy, the minor diameter, I get 12.7 mm. 1/4" BSP has a minor diameter of about 11.4 mm, while 1/4" NPS (USA) which is 0.540" 18 TPI 60° (13.716 mm x 1.411 mm), has a minor diameter of about 12.2 mm. And my 1.5 mm pitch gauge seems a near miss.

[Edit: The MX-5 itself has M16 x 1.5 threads on the hydraulics, but that's definitely not what's on the pump since that has a minor diameter of (16-1.5 =) 14.5 mm.]

Anyway, I've got a mobile hose guy coming some time this week to make up the hoses. I'll let you know what he decides it is.

I also wonder if, when they re-designated the motor terminals with plastic tags designed to blow off in a stiff breeze, after they found their pumps ran the wrong way, they adjusted the brush advance to compensate. Or whether indeed it is even possible to adjust the advance.

Those Mocen Hydraulics guys are such comedians!

But for god's sake, will someone please translate Murphy's Law into Chinese.

Last edited by weber on Tue, 04 Oct 2011, 12:42, edited 1 time in total.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

British Standard Pipe. A system where, like the incompatible USA system, the fractional inch designation is not an actual measurement, even approximately, of any aspect of the thread). 1/4" BSP is 0.518" 19 TPI 55° (13.157 mm x 1.337 mm).

Just my tuppence worth but I suspect the thread sizes are based on the nominal bore of the pipe, that is a 1/4" BSP thread would be for a 1/4"NB pipe. The nominal bore itself can lead to a whole new discussion.

Nice bracket, I'm pleased to see others work with "adjustment slots" (the 2 elongated holes) The tapered section in the fore ground of the first picture is a neat work around but I must say, the second picture does miss not have something topical in the background, possibly the can of beans with the label slightly obsured?

[quote]Here's to the crazy ones, the misfits, the rebels, the troublemakers, the round pegs in the square holes... the ones who see things differently -- they're not fond of rules... You can quote them, disagree with them, glorify or vilify them, but the only thing you can't do is ignore them because they change things... they push the human race forward, and while some may see them as the crazy ones, we see genius, because the ones who are crazy enough to think that they can change the world, are the ones who do.

Steve Jobs[/quote]

[quote]In most people's vocabularies, design means veneer. It's interior decorating. It's the fabric of the curtains or the sofa. But to me, nothing could be further from the meaning of design. Design is the fundamental soul of a human-made creation that ends up expressing itself in successive outer layers of the product or service.

Steve Jobs[/quote]

[quote]Almost everything--all external expectations, all pride, all fear of embarrassment or failure--these things just fall away in the face of death, leaving only what is truly important. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.

Steve Jobs[/quote]

[Edit: Spelling]

Last edited by weber on Sat, 08 Oct 2011, 02:40, edited 1 time in total.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

The day started with a visit from the mobile hydraulic hose guy, to connect up the power steering pump. He took the pump out to his truck to find the right adapters. When he came back with them I said, "So what are they, BSP or NPS?". He replied, "I don't know. I'm not very good with threads." ... He had just found what fitted.

He couldn't finish the job because he didn't have any right-angle thingies with him, so he'll come back next week. But he left the adapters, so I took them out and measured them. It's much easier to measure a male thread.

It turns out they are M14 x 1.5 ! Not BSP as EVWorks thought, or NPS as I thought, although either of these would probably screw into the port, given that there are only about 5 turns of the M14 thread (in which you could probably fit 5.3 turns of the slightly smaller diameter 1/4" NPS and 5.6 turns of the smaller-again 1/4" BSP). But they would risk leaking or stripping.

Then Coulomb and I worked on populating the rollbar battery box. This is the most visible battery box in the vehicle, particularly when the soft-top is folded down. So we've put our prototype BMUs on the cells in that box, for the expo.

Mum and dad came down from Maleny again to help out. Mum brought a gourmet lunch and mended carpet, did painting and made tea and coffee.

Dad ran the hose between the vacuum pump, the vacuum switch and the brake booster. We wired it up temporarily with some alligator clips and confirmed that it worked. But it does seem like we may need a reservoir, as after 3 brake pedal operations in quick succession there was very little vacuum assist.

Dad and I also reinstalled the clutch slave cylinder and pipes and hoses, and bled the system and tested it.

Sis brought fish and chips for dinner, then we watched "Harold and Maude", that exquisite black comedy from 1971 with the wonderful Cat Stevens sound track. You may remember the modifications made to an E-type Jag in the movie.

Here are its spectacular final moments. This will definitely have to be one of the optional engine-note "ring tones" for the MX-ϟ.

[Edit: Substituted longer better-quality YouTube]

Last edited by weber on Sat, 08 Oct 2011, 14:33, edited 1 time in total.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

AMPrentice wrote: Very lovely looking engine bay! dont know about the heinz can
prefer something more local if theres anything local left!

Thanks AMPrentice. I share your preference for local products. The joke was that this power steering pump has "Heinz 57 varieties" of threads and polarity markings. But hopefully, now that those are sorted, it will work well, and without too much noise. We have a plan to run it off a lower voltage to reduce noise if necessary, using an ATA speed controller.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

Good taste in movies & SF novels but this thread thread has got me discombobulated Dave. Just run the nearest tap or die you have in residence over the offending non conformist part, fill in any slack with liberal application of that white teflon tape so beloved of plumbers & it's all good ain't it?

Hi Mr B. My mum is pleased that you lick^H^Hke her paint job. But I have no idea what Coulomb is talking about. We don't have PSIs here, and I certainly wouldn't let one near the MX-5. I think he meant to say 10 MPa.

The hose wizard came yesterday morning. I might have said the "hose fairy" but in fact he calls his business Wizard Automotive Hoses, and he looks a lot more like a wizard than a fairy. Fairies tend not to have beards.

Anyway, it's all connected up very nicely. It would want to be, since it cost me $240. The pump itself was $450 + freight.

There's the 100 Hz-or-so farty noise, presumably the coginess of the 6 pole PM motor. That's not too bad. But at the same time there's this loud 5 kHz-or-so ringing noise that is beyond belief! This is presumably the tooth frequency (not the tooth fairy) of the gear pump, although it does remind one of a dentists drill.

The ringing noise can be reduced by grasping the pump motor body, but not the pump manifold block, I guess the manifold block is already deadened by being bolted to the bracket which is bolted to the traction motor, but I guess the gear pump torque harmonics are transmitted through the motor shaft and magnetically from the rotor to the magnets and hence to the motor casing they are glued inside.

I guess I'll just have to make the best of it now, but there's no way I'd use this brand of pump ever again. There has to be a better way. And maybe something smaller and less power hungry.

The motor casing has some tapped holes in it that might be used to add an extra mounting of some kind to stop the motor casing ringing.

Hopefully reducing the voltage will reduce the noise without reducing the effectiveness too much. I haven't had a chance to try that yet.

But you can forget about any kind of stealth EV driving with this puppy installed.

[Edit: Clarified pump motor versus traction motor]

Last edited by weber on Fri, 14 Oct 2011, 14:50, edited 1 time in total.

One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).